Safely Filling Silencer Holes on ported Eaton M90 Gen III Supercharger with (PICS)

I purchased an extra Eaton M90 Gen III off craigslist that i wanted to do a port and polish on. I Have never ported or polished anything and wanted to take my time doing it. Before i started to hog out the blower i did a lot of research about porting and polishing. I came to the big debate about filling the silencer holes in the output plate to increase the noise of the supercharger. Some people say its a huge risk of using jb weld or aluminum epoxy to fill the slots. If the bond fails it will fall out into the lim and grenade the motor. I do agree that it is not worth the risk of doing it the way people are talking about. So i think i came up with a safe way to block the silencer slots and not worry about bond failure and blowing your motor. I did this to my supercharger and it seems to be working great. This really lets the supercharger scream at high RPM's.

The first step is to port and polish your supercharger, Im not going into the ways of how to do the porting on it, this is simply how to block the silencer slots safely
.
As you see above this is a ported supercharger with the H bar removed, i did this because in the future i am planning
on doing an IC Setup. If you have no plans to IC then leave it there.


The next thing i did was take some thick photo paper and made a template on the output plate



Be sure to make the paper template the exact size so it fits in there as tight as possible including the tabs on the outside that fill in the
tips of the silencer ports like shown here.


Next you will need a sheet of aluminum about 1/4 to 3/8 thick. you can purchase from your local hardware store like LOWES.
Place you paper template on the aluminum and trace it out with a marker.

After you trace it out start cutting it out with a dremel or what ever tools you have access to. Be sure to cut on the outside of the template where the x's are and leave the black outline. You want to make the piece too big to fit into the supercharger so you can slowly trim it down and get the tightest fit possible.


Then start cutting it out, and (TAKE YOUR TIME)

Once you have it cut out take some sand paper and lightly sand down the sharp edges so you don't cut yourself.

now that you have it cut out and sanded the edges try to place it inside the supercharger it should be a little larger than it needs to be this is where you take a grinder and slowly take the marker off the edges making it smaller so it will eventually sit real snug down into the output plate. you want it to where you have to push it hard to get it inside flush and flat.

as you see here the plate fits snug and stays in place with out holding it there. I only grinded down the outside edge of the plate and not the inside edge. I will get to this later there is still a ledge on the inside of the triangle where the plate has a smaller opening then the triangle on the supercharger. (LEAVE IT THERE)


Next you want to scrape the surface up on the supercharger output area and the side of the plate that touches the supercharger output.

Make it like th pictures above, i used a dremel with a cutting wheel and let it bounce and scar the surface up so it was rough. I then used Carb Cleaner and sprayed the surface then scrubbed it with a wire brush and sprayed it again. Now that everything is clean and ready for a good bond tape off teh inside of the supercharger like below.




Next you want to mix up your JB WELD, make alot of it, Ratio is 1 to 1. Pour it onto the supercharger case and leave it about 3/8 thick all the way around and press your plate inplace. I used some grips to help push the plate down. allow the jb weld to flow out of all the edges like below.



Now Let it Set like this for 24 Hours and leave it alone. After you waited 24 hours pull the tape off.


It should now look like this. I let mine bake in the sun for a good 6 hours so it got real hot. Try to pick at the jb weld and make sure it is rock hard. If so then the next step is to grind everything down back to bare aluminum and try to leave as little jb weld as possible like so.

now it should look like the pics above and below.





Before Stock Eaton M90 Gen III


After Ported and Polished Eaton M90 Gen III with Custom Silencer plate.



This is the final product, I think this is a much safer way to block the silencers and this does not require any special tools. All i used was a dremel with a snake extension and alot of defferent bits. 120 gritt Flap wheels, Metel cutting wheels that go with the EZ lock bit, and wire brush wheels.

I hope this will help some people who are debating on filling the silencer holes. Sorry for the long post and lots of pics i know most people like pics to follow along with so thats why i used so many.

I was debating on drilling some screws threw the plate into the supercharger but i think this is strong enough.

I have this supercharger on my car and it am happy i made the switch its well worth it, this really lets the supercharger scream and it is very loud.

While i was doing this i was also porting my LIM and Throttle body and i came up with a 20 cent coolant delete just like the 2 cent EGR delete I think its funny so here it is




High Heat Silicone, 2 dimes, and a hammer. Works Great!

hey man awsome right up. Thats a great idea too . thanks for sharing

nice write up im curious to see how this works for you i always wondered, i thought about doing something like this but never got around to it because i purchased a GenV. as for polishing if you do it yourself its not easy and takes a long time. so good luck!

Great write up! Does blocking the silencer holes provide any benefits other than making the supercharger louder?

H bar doesnt need to be removed for ic.

I don't think so, I went from a stock supercharger to a ported lim, throttle body, and sc with this plate all at once. And I noticed a big difference. Seems to have better throttle response, boost builds quicker, and it's alot louder even under light throttle conditions. I'm running a 3.4 setup with all supporting mods and I'm getting 10-11 psi at sea level 90 deg 70% hummidity. Also the Teflon was chipping of my rotors so I striped that too, I'm sure I'm loosing some boost there, I have another set of good coated rotors I was going to swap with and see if there is a difference in boost pressure. I know theres a big argument over coated vs striped rotors so I will post what I learn after the swap some time next week.

Wheres the argument on coated or non coated?

The M62 was uncoated at first, then they added a coating and roller rockers to the SI L67 and had to go up quite a few sizes in pulley and still made more power.

Not much to argue over.

Also impressed someone actually did block off plate vs pure JB.

the argument of how much boost is lost with striped rotors. I heard guys droping 1 pulley size to compensate for striped rotors, ive yet to see a comparison of striped vs coated on the exact same setup. so thats what i was going to do in the future so i can see what the loss really is.

how much louder is the blower? was it worth it? might do it on my GenV

its probably 20% louder, i will post a video of before and after so you guys can hear the difference. the before video was same setup with stock throttle body, stock lim, and stock SC with coated rotors. the after video will be the same setup with the ported throttle body, ported lim, striped rotors, and ported SC with this plate i made.

I will post the videos soon.

BTW my current setup is 98 gtp 3.4 pulley, 160 tstat, intense standard 1.0 pcm, wrapped headers w/ 3'' down pipe, high flow cat, 3'' pipes to dynamax mufflers, FWI, AL104 plugs, P&P TB, P&P LIM, P&P SC with Custom Silencer Plate, Striped Rotors, Gator Back SC belt.

With the lim being ported for an IC, wouldn't your plate have the ability to fall into the lim. While it wouldn't fit into the runners, some of the JB still could.

Keep in mind, I'm tossing that out there, I love JB and don't doubt that if done properly it's never letting go. Although in your process you did get a seriously squared edge at the outlet. I would clean that up slightly as well.

This is what we were talking about years ago...I'm glad finally someone stepped up and goterdone.

Also...what bout dat rotor coating?

Super shot rotors.

In for win?

In for later info

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Originally Posted by matt5112

You know theres a button for that?

I do now.

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Originally Posted by matt5112

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Where?????

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